Pci Express Capability Structure - IDT 89HPES64H16G2 User Manual

IDT PCI to PCI Bridge and Proprietary Port Specific Registers

PCI Express Capability Structure

PCIECAP - PCI Express Capability (0x040)
Bit
Field
7:0
15:8
19:16
23:20
24
29:25
31:30
PCIEDCAP - PCI Express Device Capabilities (0x044)
Bit
Field
2:0 MPAYLOAD
4:3
5
PES64H16G2 User Manual
Field Default
Type
Name Value
CAPID RO 0x10
NXTPTR RWL Refer to sec-
tion Capabil-
ity Structures
on page 15-3.
VER RWL 0x2
TYPE RO Upstream:
0x5
Downstream:
0x6
SLOT RWL 0x0
IMN RO 0x0
Reserved RO 0x0
Field Default
Type
Name Value
RWL 0x4
PFS RO 0x0
ETAG RWL 0x1
Description
Capability ID. The value of 0x10 identifies this capability as a PCI
Express capability structure.
Next Pointer. This field contains a pointer to the next capability
structure.
PCI Express Capability Version. This field indicates the PCI-SIG
defined PCI Express capability structure version number.
The switch is compliant with the Express Capabilities Register
Expansion ECN.
Port Type. This field identifies the type of switch port (upstream or
downstream).
Slot Implemented. This bit is set when the PCI Express link asso-
ciated with this Port is connected to a slot. This field does not apply
to an upstream port and should be set to zero.
Interrupt Message Number. The function is allocated only one
MSI. Therefore, this field is set to zero.
Reserved field.
Description
Maximum Payload Size Supported. This field indicates the maxi-
mum payload size that the device can support for TLPs.
0x0 - (s128) 128 bytes max payload size
0x1 - (s256) 256 bytes max payload size
0x2 - (s512) 512 bytes max payload size
0x3 - (s1024) 1024 bytes max payload size
0x4 - (s2048) 2048 bytes max payload size
0x5 - (s4096) 4096 bytes max payload size
0x6 - reserved (treated as 128 bytes)
0x7 - reserved (treated as 128 bytes)
Phantom Functions Supported. This field indicates the support
for unclaimed function number to extend the number of outstand-
ing transactions allowed by logically combining unclaimed function
numbers. The value is hardwired to 0x0 to indicate that no function
number bits are used for phantom functions.
Extended Tag Field Support. This field indicates the maximum
supported size of the Tag field as a requester.
16 - 11 April 5, 2013